can then be formulated into a liposome. The principal objectives of this project are to: construct the targeting molecule; formulate it in a liposome; and verify the ability of this construct to selectively target cells that express a specific receptor. If successful, this novel targeting technology should allow: (I) the commercial production of large quantities of purified targeting molecules using standard protein isolation techniques: (2) maximum flexibility for the insertion of different targeting motifs within a standard gene cassette for the rapid development of new drug delivery vehicles; (3) easy incorporation of the targeting molecules into liposomes used for drug delivery, resulting in a commercially viable process for large scale production and: (4) elimination of the cumbersome chemical modification procedures that need to be made with other systems. Achievement of these objectives could result in a liposome-based targeting system with widespread applications for the treatment of numerous diseases, including cancer. PROPOSED COMMERCIAL APPLICATIONS: The potential commercial advantages of the technology to be developed include: an increased margin of safety because the targeted liposomes should have minimal toxic side effects: relatively straightforward procedures which make the production process less costly: and enhanced efficacy because of the improvement in targeted delivery. The proposed technology is also flexible: new targeting molecules can be made quickly and easily by simply "cutting and pasting" new antigen sequences at the proper sites in the expression vector. Given the ability to rapidly design and engineer new targeting molecules, the potential applications for this technology range from treatment of pathogenic diseases to cancers.